Method for the decomposition of octane degrading components present in tertiary butyl alcohol-gasoline additive



United States Patent 3,474,151 METHOD FOR THE DECOMPOSITION OF OCTANEDEGRADING COMPONENTS PRESENT IN TER- TIARY BUTYL ALCOHOL-GASOLINEADDITIVE Henry R. Grane, Springfield, Pa., assignor to AtlanticRichfield Company, Philadelphia, Pa., a corporation of Pennsylvania NoDrawing. Filed Oct. 26, 1966, Ser. No. 589,508 Int. Cl. C07c 29/24 US.Cl. 260-643 4 Claims ABSTRACT OF THE DISCLOSURE Method for decomposingoctane degrading components, particularly organic peroxides, in tertiarybutyl alcohol containing such components by heating the tertiary butylalcohol to from 375 F. to 475 F. for from 1 to 10 minutes.

This invention relates to a method for decomposing octane degradingcomponents present in tertiary butyl al cohol. More particularly, thisinvention relates to the decomposition of octane degrading componentspresent in tertiary butyl alcohol produced by the liquid phase oxidationof isobutane and to said alcohol and gasoline containing the same.

Although for many years tetraethyl lead and similar lead compounds havebeen added to gasolines to improve their anti-knock characteristics, inrecent years there has been a considerable amount of work directedtoward the production of gasolines which are either free of tetraethyllead or are of low tetraethyl lead content. There are two importantreasons for reducing the lead content of gasolines, the first being thatlead produces harmful deposits in internal combustion engines whichrequires the addition to the gasoline of various types of scavengers anddeposit modifiers. In addition, there has been a gradually increasingpressure from public health authorities to reduce or eliminate entirelythe lead content of gasoline because of the toxic effect thereof.

Carburetor icing is another problem of modern automotive engines.Carburetor icing causes stalling of the engine in cool, humid weather,particularly when the englue is cold. It has been found that whentertiary butyl alcohol (2-methyl-2-propanol) is added to gasoline thecarburetor anti-icing properties of the gasoline are markedly improvedand, in addition, since tertiary butyl alcohol is an anti-knock compoundthe addition of tertiary butyl alcohol to gasoline provides a two-wayimprovement to the gasoline, i.e. it improves the anti-knockcharacteristics and the anti-icing properties of the gasoline. Ingeneral the amount of tertiary butyl alcohol added to gasoline for thesepurposes ranges in amount from 1 volume percent to 20 volume percentbased on the total volume of the fuel.

One of the most convenient methods of making tertiary butyl alcohol isby the oxidation of isobutane in the liquid phase using molecularoxygen. In this method the oxidation is carried out, preferably in theabsence of catalytic materials, at temperatures in the range of fromabout 200 F. to 300 F. or preferably in the range of from 260 F. to 290F. at pressures of from 300 p.s.i. to 700 p.s.i. although theseconditions can be varied somewhat. When the tertiary butyl alcohol isproduced by this method there is also produced tertiary butylhydroperoxide in amounts which may equal or exceed the amount oftertiary butyl alcohol. In addition ditertiary butyl peroxide and otheroxygenated compounds are produced in small amounts. The tertiary butylhydroperoxide is a valuable oxidizing agent which may be used in manyways, for example, to oxidize olefins to epoxides. The hydroperoxide mayeither be separated from the alcohol for 3,474,151- Patented Oct. 21,1969 this purpose or the entire product of the isobutane oxidation, i.e.the tertiary butyl hydroperoxide which has not been separated from thetertiary butyl alcohol and minor oxygenated compounds, may be used forthe oxidation reaction. The residual tertiary butyl alcohol by eithermethod does, however, contain some tertiary butyl hydroperoxide andperoxides. Although these compounds may be present in relatively smallquantities in the tertiary butyl alcohol they have a large degradationeffect on the octane characteristics of the gasoline. It has been foundthat the total peroxy content of the alcohol to be added to gasolineshould be less than 100 p.p.m. by Weight of the tertiary butyl alcohol.

In accordance with this invention a method has been found for treatingtertiary butyl alcohol containing hydroperoxides and peroxides todecompose these components which are octane degrading.

It is an object of this invention therefore to provide a method for thedecomposition of octane degrading components in tertiary butyl alcohol.

It is another object of this invention to provide tertiary butyl alcoholwhich has been treated to decompose octane degrading components.

It is another object of this invention to provide gasoline containingtertiary butyl alcohol treated to decompose octane degrading components.

Further objects of this invention will be apparent from the followingdetailed description and from the claims.

It has been found that if tertiary butyl alcohol containing smallquantities of hydroperoxides and peroxides is heated to a temperature inthe range of from 375 F. to 475 F., preferably from 400 F. to 450 F.,for at least 1 minute and generally from 1 to 10 minutes either in thevapor phase or the liquid phase that the hydroperoxides and peroxidesare decomposed substantially completely into compounds which are notoctane degrading. Since tertiary butyl alcohol starts to dehydrate evenat 450 F. the shorter times should be used with the higher temperatures,but above 475 F. the dehydration is so rapid it destroys the desiredalcohol even with very short times. Pressures ranging from atmosphericto 1000 p.s.i.g. or higher can be used, depending upon Whether thereaction is carried out in the gas phase or liquid phase. However, it isdesirable to utilize sufiicient pressure to carry out the treatment inthe liquid phase since this requires smaller equipment and thus lesscapital investment. In general pressures of from 500 p.s.i.g. to 700p.s.i.g. are desirable primarily for economic reasons.

The examples which follow are provided to illustrate more specificallythe invention. It will be understood, however, that these examples aremerely illustrative of a large number of runs which have been carriedout to de- EXAMPLE I A sample of isobutane was oxidized in the liquidphase utilizing molecular oxygen and the oxidation product was utilizedto epoxidize propylene. After the propylene oxide had been separated bydistillation there remained tertiary butyl alcohol containing 1.2 weightpercent tertiary butyl hydroperoxide, 0.4 weight percent ditertiarybutyl peroxide and 1.3 weight percent allyl tertiary butyl peroxidebased on the weight of the tertiary butyl alcohol plus impurities. Asample of this tertiary butyl alcohol was heated for 8 minutes at 406 F.under a pressure of 602 p.s.i.g. The product was found to contain lessthan 10 p.p.m. by weight of each of the hydroperoxide and peroxideimpurities. This run demonstrates that heat treatment of tertiary butylalcohol in accordance wih this invention decomposes substantiallycompletely the hydroperoxide and peroxide impurities in the tertiarybutyl alcohol.

EXAMPLE II In order to demonstrate that the heat treatment of tertiarybutyl alcohol in accordance with his invention decomposes the octanedegrading components, three comparative tests were made. To a premiumgrade gasoline containing 3 ml. of tetraethyl lead per gallon was added10 volume percent based on the total volume of the fuel of highlypurified tertiary butyl alcohol which was free of hydroperoxides andperoxides and contained less than one weight percent of totalimpurities. Another 10 percent blend in the same gasoline was made withtertiary butyl alcohol containing substantially the same quantities ofhydroperoxides and peroxides as the tertiary butyl alcohol described inExample I before heat treatment. Another sample of this impure tertiarybutyl alcohol was heat treated at 419 F. in the liquid phase at 600p.s.i.g. for 3 minutes. The product from this heat treatment wasutilized to make a 10 volume percent blend with the same gasolineutilized in the first two blends of this example. Each of these threeblends was tested for octane number both by the Research Octane Method(ASTM Method D-908) and the Motor Octane Method (ASTM D-357). The blendcontaining the impure tertiary butyl alcohol before heat treatment wasfound to degrade the Research Octane number by 2.2 numbers below theResearch Octane number for the gasoline blend containing the puretertiary butyl alcohol. When the gasoline containing the impure tertiarybutyl alcohol was tested by the Motor Method it was found that theoctane number was lowered by 1.07 numbers below the Motor Method octantnumber of the gasoline containing the pure tertiary butyl alcohol. Thegasoline containing the tertiary butyl alcohol which had been heattreated to decompose the octane degrading components had the sameResearch Octane number as the gasoline containing the pure tertiarybutyl alcohol and a slightly higher (+0.26) Motor Octane number than thegasoline containing the pure tertiary butyl alcohol. These runsdemonstrate that the heat treatment of tertiary butyl alcohol inaccordance with this invention decomposes the octant degradingcomponents of the impure material and gives a product which is the sameas chemically pure tertiary butyl alcohol.

I claim:

1. A method for decomposing octane degrading components from tertiarybutyl alcohol which consists of heating the tertiary butyl alcoholcontaining small quantities of organic peroxides to a temperature in therange of from 375 F. to 475 F. for a time of from 1 minute to 10minutes.

2. The process according to claim 1 wherein the temperature is in therange of from 400 F. to 450 F.

3. The process according to claim 1 wherein the tertiary butyl alcoholis produced by the oxidation of isobutane.

4. The process according to claim 1 wherein the temperature is in therange of from 400 F. to 450 F. and the time is in the range of from 5minutes to 9 minutes.

References Cited UNITED STATES PATENTS 1,845,665 2/1932 Isham 2606821,984,725 12/1934 Britton et al. 260643 2,478,270 8/1949 Ipatiefr et a1260682 2,615,921 10/1952 Dougherty ct al.

2,671,121 3/1954 Banes et al. 260682 2,700,677 1/1955 Bowen et al.260643 3,351,635 11/1967 Kollar 260682 OTHER REFERENCES Tobolsky et al.,Organic Peroxide's (1954), pp. 92, 93, QD181.01T6.

Hawkins, Organic Peroxides, (1961), pp. 7 and 13 to 17, QD305.H7HJ 8.

LEON ZITVER, Primary Examiner J. E. EVANS, Assistant Examiner U.S. Cl.X.R. 44-56; 260349.5

